Apple's iCal has been updated.

iCal 1.5.5 improves iSync synchronization in Mac OS X 10.2.

It also includes security enhancements found in iCal 1.3.4. These help protect your computer when subscribing to calendars or importing events with alarms that open files or applications.

The software lets you maintain multiple calendars in a single window. Calendars can be hosted on .Mac, and shared online with friends, colleagues, and family. Calendars can also be synced with other Macs and iPods, mobile phones, and PDAs – iSync 1.2.1 or later is required. iCal is free.